The present invention relates to zwitterionic organic catalyst compound bleach systems and methods for using such bleach systems to provide increased color safety during laundering of fabrics, especially colored fabrics. More particularly, this invention relates to bleach systems comprising zwitterionic, quaternary imine bleach boosting compounds, zwitterionic, quaternary oxaziridinium bleaching species and mixtures thereof, and methods employing such bleach systems in the laundering of fabrics, especially colored fabrics.
Oxygen bleaching agents have become increasingly popular in recent years in household and personal care products to facilitate stain and soil removal. Bleaches are particularly desirable for their stain-removing, dingy fabric cleanup, whitening and sanitization properties. Oxygen bleaching agents have found particular acceptance in laundry products such as detergents, in automatic dishwashing products and in hard surface cleansers. Oxygen bleaching agents, however, are somewhat limited in their effectiveness. Some frequently encountered disadvantages include color damage on fabrics and damage to laundry appliances, specifically rubber hoses these appliances may contain. In addition, oxygen bleaching agents tend to be extremely temperature rate dependent. Thus, the colder the solution in which they are employed, the less effective the bleaching action. Temperatures in excess of 60xc2x0 C. are typically required for effectiveness of an oxygen bleaching agent in solution.
To solve the aforementioned temperature rate dependency, a class of compounds known as xe2x80x9cbleach activatorsxe2x80x9d has been developed. Bleach activators, typically perhydrolyzable acyl compounds having a leaving group such as oxybenzenesulfonate, react with the active oxygen group, typically hydrogen peroxide or its anion, to form a more effective peroxyacid oxidant. It is the peroxyacid compound which then oxidizes the stained or soiled substrate material. However, bleach activators are also somewhat temperature dependent. Bleach activators are more effective at warm water temperatures of from about 40xc2x0 C. to about 60xc2x0 C. In water temperatures of less than about 40xc2x0 C., the peroxyacid compound loses some of its bleaching effectiveness.
U.S. Pat. Nos. 5,576,282 and 5,817,614 both to Miracle et al. disclose attempts at developing bleach systems comprising zwitterionic organic catalyst compounds which are effective in lower temperature water conditions and are relatively safe on colors. Although the bleach systems disclosed in this patent provide enhanced color-safety over traditional organic catalyst bleach systems, such as cationic, organic catalyst bleach systems examples of which are disclosed in U.S. Pat. Nos. 5,360,568, 5,360,569, 5,370,826 and 5,482,515 all to Madison et al., consumers desire more color-safe bleach products.
A serious disadvantage associated with methods of using conventional organic catalysts, examples of which are described in U.S. Pat. Nos. 5,360,568, 5,360,569 and 5,370,826 all to Madison et al., and U.S. Pat. Nos. 5,576,282 and 5,817,614, both to Miracle et al., is that such organic catalysts are used at too high an in-use concentration. For example, the method used in U.S. Pat. No. 5,482,515 describes a method wherein the oxygen transfer agent (an organic catalyst compound) is present from about 0.01 ppm to 300 ppm, with the preferred concentration range from 5 ppm to about 100 ppm per liter of medium. Such a concentration can result in unacceptable color damage to fabric dyes. In addition, such a high concentration can lead to too much available oxygen (xe2x80x9cAvOxe2x80x9d) consumption, leading to an altered performance profile (i.e., changing the balance between peracid bleaching and organic catalyst bleaching). It may be possible to increase stain bleaching performance with increased organic catalyst concentration but only at the cost of dye damage and at some point the dye damage becomes unacceptable. Accordingly, there is a need to maximize the ratio of stain bleaching performance to dye damage of the organic catalyst bleach systems.
In light of the foregoing, it is evident that there still exists a need for zwitterionic organic catalyst compound bleach systems and laundry methods employing such zwitterionic organic catalyst compound bleach systems that provide effective bleaching in lower temperature water conditions and provide. superior color-safety properties compared to the laundry methods employing the organic catalyst bleach systems disclosed in the prior art, as discussed above; and there is a need to maximize the ratio of stain bleaching performance to dye damage of the organic catalyst bleach systems.
The present invention fulfills the need discussed above. The present invention provides zwitterionic organic catalyst compound bleach systems and methods for laundering fabrics, especially colored fabrics, employing such bleach systems.
The zwitterionic organic catalyst compounds of the present invention, and bleach systems comprising such zwitterionic organic catalyst compounds provide increased bleaching effectiveness in lower temperature wash applications while providing improved color safety, resulting in increased bleaching effectiveness and color safety as compared to conventional zwitterionic and cationic organic catalyst bleach systems. The zwitterionic organic catalyst compound bleach systems of the present invention act in conjunction with or without, preferably with, conventional peroxygen bleaching sources to provide the above-mentioned increased bleaching effectiveness and superior fabric color safety.
More particularly, this invention relates to zwitterionic organic catalyst compounds such as zwitterionic, quaternary imine bleach boosting compounds, zwitterionic, quaternary oxaziridinium bleaching species, bleach systems comprising such zwitterionic organic catalyst compounds and laundry methods employing such bleach systems.
Nonlimiting examples of the benefits provided by the zwitterionic organic catalyst compounds and bleach systems employing same include superior bleaching effectiveness even in lower temperature water, and improved color safety.
In one aspect of the present invention, a zwitterionic organic catalyst bleach system which demonstrates effective bleaching in lower water temperature and provides a superior color-safety profile compared to the conventional organic catalyst bleach systems is provided.
In accordance with another aspect of the present invention, a zwitterionic organic catalyst bleach system comprising one or more zwitterionic organic catalyst compounds, as described hereinafter, in conjunction with or without a peroxygen source is provided.
In accordance with yet another aspect of the present invention, a zwitterionic organic catalyst bleach system comprising one or more zwitterionic organic catalyst compounds, as described hereinafter, in conjunction with a peracid is provided.
In accordance with still yet another aspect of the present invention, a method for laundering a fabric, especially a colored fabric, in need of laundering comprising contacting the fabric with a laundry solution comprising one or more zwitterionic organic catalyst compound bleach systems described herein is provided.
In accordance with even still yet another aspect of the present invention, a bleach system of the present invention as made by the process comprising:
a) providing a wash solution; and
b) adding to said wash solution a bleach composition comprising an
amount of zwitterionic organic catalyst compound of the present invention such that the resulting concentration of the zwitterionic organic catalyst compound in said wash solution is from about 0.001 ppm to about 5 ppm, is provided.
Accordingly, it is an object of the present invention to provide: zwitterionic organic catalyst compound bleach systems, which demonstrate improved performance even in lower temperature water solutions and improved color safety; and a method for laundering a fabric, especially a colored fabric, using one or more of the zwitterionic organic catalyst compound bleach systems described herein.
These and other objects, features and advantages of the present invention will be recognized by one of ordinary skill in the art from the following description and the appended claims.
All percentages, ratios and proportions herein are on a weight basis unless otherwise indicated. All documents cited herein are hereby incorporated by reference.